1. Field of the Invention
The present invention relates to a technique useful for recognizing a touch operation.
2. Description of the Related Art
In recent years, touch input devices including a touch-screen have been widely used. When a user touches the screen with a finger or a stylus, the X and Y coordinates of the touched position are obtained as input values. Various types of processing are performed based on this input value. Further, techniques for multi-touch, which allows sensing of two or more points on a surface of a screen, are developing. According to this multi-touch operation, the user can perform various operations such as enlarge, reduce, and scroll of a text by touching two points on the screen, for example, with the thumb and the index finger of the right hand.
In such a case, a large screen close to the size of an entire device is desirable as the touch input device. If the device has the large screen, however, the user may inadvertently touch the screen when holding the input device. If the user touches the screen of a touch input device capable of multi-touch operation, unintended touch input may be recognized by the device despite the user's intention. This may result in false operation.
A technique for invalidating the unintended touch point is discussed in Japanese Patent Application Laid-Open No. 2011-180943. According to Japanese Patent Application Laid-Open No. 2011-180943, if an information processing terminal is tilted by a predetermined degree from a horizontal position and if a predetermined point is continuously touched for a predetermined period of time, it is considered that the point is touched by the user to hold the terminal device, and the touch point is invalidated.
The information processing apparatus which is operated by touch or multi-touch is assumed to be used in various positions. Thus, it is not always appropriate to determine whether a touch point should be invalidated by detecting whether the apparatus is tilted by a predetermined angle or more as discussed in Japanese Patent Application Laid-Open No. 2011-180943.